A group of scientists from Columbia University in the course of two studies found new ways to combat baldness (hair loss).
In the first study, scientists led by Angela Christiano, MD, professor of dermatology, discovered previously unknown cells that support follicles in mice at rest, and showed that suppressing these cells can awaken dormant hair follicles.
In the second study, a group led by Cristiano created a method for growing human hair “in vitro” (in fact, in an environment created using 3D printing), opening a new path for hair restoration operations and improving methods for finding new drugs for hair growth.
The essence of new research to combat baldness
With baldness, many hair follicles remain, but are at rest. The search for new drugs that awaken follicles and stimulate hair growth was limited by the fact that research focused on drugs that work in the same ways that are already known and available today for men with male pattern baldness finasteride (suppression of the formation of dihydrotestosterone) and minoxidil (improvement of blood supply to hair follicles).
Dissatisfied with this state of affairs, Cristiano and her colleagues set a goal to deal directly with the biochemical mechanism of baldness. Previously, they have already shown that janus kinase inhibitors used in mice can be a powerful means of awakening hair follicles that were at rest. In the new study, the scientists wanted to get a detailed picture of the processes that keep the follicles in a dormant state.
They suggested that the JAK-STAT signaling pathway is involved in keeping hair follicle stem cells dormant, acting inside the cell and transmitting signals to the transcription-activating protein of the STAT family from cytokines, in particular from the oncostatin M protein, which has previously been associated with the deterioration of hair growth. In the course of their work, they sequenced the RNA of a single hair follicle cell and found out that it does not encode the production of oncostatin M, that is, this cytokine is external to the follicle cell, introduced.
In the process of searching for the source of this protein, scientists found out that oncostatin M is produced by a previously unknown type of macrophages, immune cells that enrich themselves in the sleeping stem cell of the hair follicle and die in it, leaving the hospitable host with oncostatin M, which keeps the follicle stem cell in a dormant state and does not allow its proliferation and hair growth to start.
Most of the drug developments are focused on the treatment of hair loss in men, it is on them that most of the clinical trials are conducted. “The pathways we have discovered may lead to new treatments for both men and women suffering from hair loss, since it acts independently of the male hormonal pathways,” says Cristiano. – It is important that this will help to avoid the side effects seen with the use of finasteride and minoxidil. Especially if the treatment will be carried out locally.”
The second study
In the second study, scientists from Columbia University have created a way to grow hair in a test tube. It may allow hair restoration operations for many people, including women, as well as simplify the search for new drugs that ensure hair growth.
For the first time, human hair follicles were fully formed in a test tube without implantation into the skin.
For many years, it has been possible to grow mouse or rat hair by culturing cells taken from existing follicles. “The cells of rats and mice allow you to grow beautiful hair,” says Cristiano. “But, for reasons we don’t understand, the human cells resisted.”
To overcome the resistance of human hair cells, Cristiano tries to create conditions that mimic the environment common to human hair follicles. Initially, the laboratory tried to create small spheres of cells inside liquid droplets. But when these spheres were implanted in mice, the results were unpredictably unstable: some human cells formed new hair, while others did not.
Combat baldness: research details
In their study, a group led by Cristiano used the capabilities of 3D printers to create a natural microenvironment for hair follicle growth.
The researchers used 3D printing to create plastic molds with long, thin growths only half a millimeter wide. “Previous manufacturing technologies did not allow us to create such thin outgrowths, our work was greatly facilitated thanks to three-dimensional printing,” says the lead author of this study, Erbil Abaci.
After the human skin was designed so that it could grow around the dummy, the follicle hair cells of the volunteers were placed in the recesses and covered with keratin-producing cells. The cells were provided with various conditions for growth — they were fueled by various ingredients, including janus kinase inhibitors that stimulate hair growth, according to the laboratory.
After three weeks, hair follicles appeared, which began to create hair.
Although such a method needs to be optimized, the human hair follicles created in this way can indefinitely generate a source of new hair follicles for patients undergoing robotic hair restoration surgery.
Such an operation requires the transfer of approximately 2,000 hair follicles from the back of the head to the forehead and crown.
“We have shown that we can create a hair production farm — a mesh of hair properly structured in such a way that they can be transplanted back into the scalp of the same patient,” says Cristiano. – This expands access to hair restoration services for all patients, including women experiencing thinning hair and young men whose hair is thinning. The restoration operation will no longer be limited by the number of donor hairs.”
The created follicles can also be used by the pharmaceutical industry to find new drugs for hair growth. This is important, because up to this point, the high-performance direct search for new drugs was difficult due to the impossibility of growing human hair follicles in a test tube. Strictly speaking, no drug for hair growth has been found by targeted screening — even finasteride and minoxidil, approved today for the treatment of alopecia, have been discovered and investigated as drugs against other diseases.